/*=========================================================================

  Program:   Visualization Toolkit
  Module:    vtkLoopBooleanPolyDataFilter.cxx

  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
  All rights reserved.
  See Copyright.txt or http://www.kitware.com/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notice for more information.

=========================================================================*/
/** @file vtkLoopBooleanPolyDataFilter.cxx
 *  @brief This is the filter to perform boolean operations
 *  @author Adam Updegrove
 *  @author updega2@gmail.com
 */

#include "vtkLoopBooleanPolyDataFilter.h"

#include "vtkAppendPolyData.h"
#include "vtkCellArray.h"
#include "vtkCellData.h"
#include "vtkCleanPolyData.h"
#include "vtkDoubleArray.h"
#include "vtkFloatArray.h"
#include "vtkGenericCell.h"
#include "vtkInformation.h"
#include "vtkInformationVector.h"
#include "vtkIntersectionPolyDataFilter.h"
#include "vtkMath.h"
#include "vtkMergeCells.h"
#include "vtkObjectFactory.h"
#include "vtkPointData.h"
#include "vtkPointLocator.h"
#include "vtkPolyDataNormals.h"
#include "vtkSmartPointer.h"
#include "vtkTransform.h"
#include "vtkTransformPolyDataFilter.h"
#include "vtkTriangle.h"
#include "vtkUnstructuredGrid.h"

#include <iostream>
#include <list>
#include <sstream>
#include <string>

//------------------------------------------------------------------------------
// Helper typedefs and data structures.
namespace
{

struct simLine
{
  vtkIdType id;
  vtkIdType pt1;
  vtkIdType pt2;
};

struct simLoop
{
  std::list<simLine> cells;
  vtkIdType startPt;
  vtkIdType endPt;
  int loopType;
};

}

// Implementation function
class vtkLoopBooleanPolyDataFilter::Impl
{
public:
  Impl();
  virtual ~Impl();

  void Initialize();
  void SetCheckArrays();
  void SetBoundaryArrays();
  void ResetCheckArrays();
  void GetBooleanRegions(int inputIndex, std::vector<simLoop>* loops);
  void DetermineIntersection(std::vector<simLoop>* loops);
  void PerformBoolean(vtkPolyData* output, int booleanOperation);
  void ThresholdRegions(vtkPolyData** surfaces);

protected:
  int RunLoopFind(vtkIdType interPt, vtkIdType nextCell, bool* usedPt, simLoop* loop);

  int RunLoopTest(vtkIdType interPt, vtkIdType nextCell, simLoop* loop, bool* usedPt);

  int GetCellOrientation(vtkPolyData* pd, vtkIdType cellId, vtkIdType p0, vtkIdType p1, int index);

  int FindRegion(int inputIndex, int fillnumber, int start, int fill);

  int FindRegionTipToe(int inputIndex, int fillnumber, int fill);

public:
  int IntersectionCase;

  vtkPolyData* Mesh[2];
  vtkPolyData* IntersectionLines;

  vtkIntArray* BoundaryPointArray[2];
  vtkIntArray* BoundaryCellArray[2];
  vtkIntArray* BooleanArray[2];
  vtkIntArray* NewCellIds[2];

  vtkIdType* Checked[2];
  vtkIdType* CheckedCarefully[2];
  vtkIdType* PointMapper[2];
  vtkIdType* ReversePointMapper[2];

  vtkIdList* CheckCells;
  vtkIdList* CheckCells2;
  vtkIdList* CheckCellsCareful;
  vtkIdList* CheckCellsCareful2;

  // Pointer to overarching filter
  vtkLoopBooleanPolyDataFilter* ParentFilter;
};

vtkLoopBooleanPolyDataFilter::Impl::Impl()
  : CheckCells(nullptr)
  , CheckCells2(nullptr)
  , CheckCellsCareful(nullptr)
  , CheckCellsCareful2(nullptr)
{
  for (int i = 0; i < 2; i++)
  {
    this->Mesh[i] = vtkPolyData::New();

    this->BooleanArray[i] = vtkIntArray::New();
    this->BoundaryPointArray[i] = vtkIntArray::New();
    this->BoundaryCellArray[i] = vtkIntArray::New();
    this->NewCellIds[i] = vtkIntArray::New();

    this->Checked[i] = nullptr;
    this->CheckedCarefully[i] = nullptr;
    this->PointMapper[i] = nullptr;
    this->ReversePointMapper[i] = nullptr;
  }
  this->IntersectionLines = vtkPolyData::New();
  this->CheckCells = vtkIdList::New();
  this->CheckCells2 = vtkIdList::New();
  this->CheckCellsCareful = vtkIdList::New();
  this->CheckCellsCareful2 = vtkIdList::New();

  // Intersection Case:
  // 0 -> Only hard closed intersection loops
  // 1 -> At least one soft closed intersection loop
  // 2 -> At least one open intersection loop
  this->IntersectionCase = 0;
}

vtkLoopBooleanPolyDataFilter::Impl::~Impl()
{
  for (int i = 0; i < 2; i++)
  {
    this->Mesh[i]->Delete();
    this->BooleanArray[i]->Delete();
    this->BoundaryPointArray[i]->Delete();
    this->BoundaryCellArray[i]->Delete();
    this->NewCellIds[i]->Delete();

    delete[] this->Checked[i];
    delete[] this->CheckedCarefully[i];
    delete[] this->PointMapper[i];
    delete[] this->ReversePointMapper[i];
  }
  this->IntersectionLines->Delete();
  this->CheckCells->Delete();
  this->CheckCells2->Delete();
  this->CheckCellsCareful->Delete();
  this->CheckCellsCareful2->Delete();
}

// Flood fill algorithm to find region of mesh separated by intersection lines
int vtkLoopBooleanPolyDataFilter::Impl::FindRegion(
  int inputIndex, int fillnumber, int start, int fill)
{
  vtkDebugWithObjectMacro(this->ParentFilter, << "Finding region with fill " << fillnumber
                                              << " of mesh " << inputIndex << " with cellID "
                                              << this->CheckCells->GetId(0));

  // Id List to store neighbor cells for each set of nodes and a cell
  vtkSmartPointer<vtkIdList> neighbors = vtkSmartPointer<vtkIdList>::New();
  vtkSmartPointer<vtkIdList> tmp = vtkSmartPointer<vtkIdList>::New();

  vtkIdType numCheckCells;
  // Get neighboring cell for each pair of points in current cell
  // While there are still cells to be checked, find neighbor cells
  while ((numCheckCells = this->CheckCells->GetNumberOfIds()) > 0)
  {
    for (int c = 0; c < numCheckCells; c++)
    {
      vtkIdType cellId = this->CheckCells->GetId(c);
      // Get the three points of the cell
      const vtkIdType* pts = nullptr;
      vtkIdType npts = 0;
      this->Mesh[inputIndex]->GetCellPoints(cellId, npts, pts);
      if (this->Checked[inputIndex][cellId] == 0)
      {
        // Mark cell as checked and insert the fillnumber value to cell
        if (fill)
        {
          this->BooleanArray[inputIndex]->InsertValue(cellId, fillnumber);
        }
        this->Checked[inputIndex][cellId] = 1;
        for (int i = 0; i < npts; i++)
        {
          vtkIdType p1 = pts[i];
          // Get the cells attached to each point
          this->Mesh[inputIndex]->GetPointCells(p1, neighbors);
          vtkIdType numNeighbors = neighbors->GetNumberOfIds();

          // For each neighboring cell
          for (int j = 0; j < numNeighbors; j++)
          {
            // If this cell is close to a boundary
            if (this->BoundaryCellArray[inputIndex]->GetValue(neighbors->GetId(j)))
            {
              // If this cell hasn't been checked already
              if (this->CheckedCarefully[inputIndex][neighbors->GetId(j)] == 0)
              {
                // Add this cell to the careful check cells list and run
                // the region finding tip toe code
                this->CheckCellsCareful->InsertNextId(neighbors->GetId(j));
                if (fill)
                {
                  this->FindRegionTipToe(inputIndex, fillnumber, 1);
                }
                else
                {
                  this->FindRegionTipToe(inputIndex, fillnumber, 0);
                }
                this->CheckCellsCareful->Reset();
                this->CheckCellsCareful2->Reset();
              }
            }
            // Cell needs to be added to check list
            else
            {
              this->CheckCells2->InsertNextId(neighbors->GetId(j));
            }
          }
        }
      }
      // This statement is for if the start cell is a boundary cell
      else if (this->CheckedCarefully[inputIndex][cellId] == 0 && start)
      {
        start = 0;
        this->CheckCells->Reset();
        this->CheckCellsCareful->InsertNextId(cellId);
        if (fill)
        {
          this->FindRegionTipToe(inputIndex, fillnumber, 1);
        }
        else
        {
          this->FindRegionTipToe(inputIndex, fillnumber, 0);
        }
      }
    }

    // Swap the current check list to the full check list and continue
    tmp = this->CheckCells;
    this->CheckCells = this->CheckCells2;
    this->CheckCells2 = tmp;
    tmp->Reset();
  }
  return 1;
}

// This is the slow version of the flood fill algorithm that is initiated
// when we get close to a boundary to ensure we don't cross the line
int vtkLoopBooleanPolyDataFilter::Impl::FindRegionTipToe(int inputIndex, int fillnumber, int fill)
{
  // Id List to store neighbor cells for each set of nodes and a cell
  vtkSmartPointer<vtkIdList> tmp = vtkSmartPointer<vtkIdList>::New();
  vtkSmartPointer<vtkIdList> neighborIds = vtkSmartPointer<vtkIdList>::New();

  vtkIdType numCheckCells;
  // Get neighboring cell for each pair of points in current cell
  // While there are still cells to be checked
  while ((numCheckCells = this->CheckCellsCareful->GetNumberOfIds()) > 0)
  {
    for (int c = 0; c < numCheckCells; c++)
    {
      neighborIds->Reset();
      vtkIdType cellId = this->CheckCellsCareful->GetId(c);
      // Get the three points of the cell
      const vtkIdType* pts = nullptr;
      vtkIdType npts = 0;
      this->Mesh[inputIndex]->GetCellPoints(cellId, npts, pts);
      // Update this cell to have been checked carefully and assign it
      // with the fillnumber scalar
      if (this->CheckedCarefully[inputIndex][cellId] == 0)
      {
        if (fill)
        {
          this->BooleanArray[inputIndex]->InsertValue(cellId, fillnumber);
        }
        this->CheckedCarefully[inputIndex][cellId] = 1;
        // For each edge of the cell
        vtkDebugWithObjectMacro(this->ParentFilter, << "Checking edges of cell " << cellId);
        for (int i = 0; i < npts; i++)
        {
          vtkIdType p1 = pts[i];
          vtkIdType p2 = pts[(i + 1) % (npts)];

          vtkSmartPointer<vtkIdList> neighbors = vtkSmartPointer<vtkIdList>::New();
          // Initial check to make sure the cell is in fact a face cell
          this->Mesh[inputIndex]->GetCellEdgeNeighbors(cellId, p1, p2, neighbors);
          vtkIdType numNeighbors = neighbors->GetNumberOfIds();

          // Check to make sure it is an oustide surface cell,
          // i.e. one neighbor
          if (numNeighbors == 1)
          {
            int count = 0;
            // Check to see if cell is on the boundary,
            // if it is get adjacent lines
            if (this->BoundaryPointArray[inputIndex]->GetValue(p1) == 1)
            {
              count++;
            }

            if (this->BoundaryPointArray[inputIndex]->GetValue(p2) == 1)
            {
              count++;
            }

            vtkIdType neighbor = neighbors->GetId(0);
            // if cell is not on the boundary, add new cell to check list
            if (count < 2)
            {
              neighborIds->InsertNextId(neighbor);
            }
            // if cell is on boundary, check to make sure it isn't
            // false positive; don't add to check list. This is done by
            // getting the boundary lines attached to each point, then
            // intersecting the two lists. If the result is zero, then this
            // is a false positive
            else
            {
              // Variables for the boundary cells adjacent to the boundary point
              vtkSmartPointer<vtkIdList> bLinesOne = vtkSmartPointer<vtkIdList>::New();
              vtkSmartPointer<vtkIdList> bLinesTwo = vtkSmartPointer<vtkIdList>::New();

              vtkIdType bPt1 = PointMapper[inputIndex][p1];
              this->IntersectionLines->GetPointCells(bPt1, bLinesOne);

              vtkIdType bPt2 = PointMapper[inputIndex][p2];
              this->IntersectionLines->GetPointCells(bPt2, bLinesTwo);

              bLinesOne->IntersectWith(bLinesTwo);
              // Cell is false positive. Add to check list.
              if (bLinesOne->GetNumberOfIds() == 0)
              {
                vtkDebugWithObjectMacro(this->ParentFilter, << "False positive! " << neighbor);
                neighborIds->InsertNextId(neighbor);
              }
              else
              {
                vtkDebugWithObjectMacro(
                  this->ParentFilter, << "I have not been added because false");
              }
            }
          }
          else
          {
            vtkDebugWithObjectMacro(this->ParentFilter, << "NumNei is not 1");
            vtkDebugWithObjectMacro(this->ParentFilter, << "Number of Neighbors " << numNeighbors);
            vtkDebugWithObjectMacro(this->ParentFilter, << "Cell is " << cellId);
            for (int k = 0; k < numNeighbors; k++)
            {
              vtkDebugWithObjectMacro(this->ParentFilter, << "Id!!! " << neighbors->GetId(k));
            }
          }
        }

        vtkIdType numIds = neighborIds->GetNumberOfIds();
        if (numIds > 0)
        {
          // Add all Ids in current list to global list of Ids
          for (int k = 0; k < numIds; k++)
          {
            vtkIdType neighborId = neighborIds->GetId(k);
            if (this->CheckedCarefully[inputIndex][neighborId] == 0)
            {
              this->CheckCellsCareful2->InsertNextId(neighborId);
            }
            else if (this->Checked[inputIndex][neighborId] == 0)
            {
              this->CheckCells2->InsertNextId(neighborId);
            }
          }
        }
      }
    }

    // Add current list of checked cells to the full list and continue
    tmp = this->CheckCellsCareful;
    this->CheckCellsCareful = this->CheckCellsCareful2;
    this->CheckCellsCareful2 = tmp;
    tmp->Reset();
  }
  return 1;
}

void vtkLoopBooleanPolyDataFilter::Impl::Initialize()
{
  for (int i = 0; i < 2; i++)
  {
    if (this->Mesh[i]->GetNumberOfPoints() == 0 || this->Mesh[i]->GetNumberOfCells() == 0)
    {
      vtkGenericWarningMacro(<< "Mesh has zero points or cells and "
                             << "cannot run filter");
      return;
    }

    // Get the number of Polys for scalar allocation
    int numPolys = this->Mesh[i]->GetNumberOfPolys();
    int numPts = this->Mesh[i]->GetNumberOfPoints();
    int numLinePts = this->IntersectionLines->GetNumberOfPoints();

    // Allocate space for each Boundary Array and the fill array
    this->BoundaryPointArray[i]->SetNumberOfTuples(numPts);
    this->BoundaryCellArray[i]->SetNumberOfTuples(numPolys);
    this->BooleanArray[i]->SetNumberOfTuples(numPolys);
    this->Checked[i] = new vtkIdType[numPolys];
    this->CheckedCarefully[i] = new vtkIdType[numPolys];
    this->PointMapper[i] = new vtkIdType[numPolys];
    this->ReversePointMapper[i] = new vtkIdType[numLinePts];

    for (int j = 0; j < numPts; j++)
    {
      this->BoundaryPointArray[i]->InsertValue(j, 0);
    }
    for (int j = 0; j < numPolys; j++)
    {
      this->BoundaryCellArray[i]->InsertValue(j, 0);
      this->BooleanArray[i]->InsertValue(j, 0);
      this->Checked[i][j] = 0;
      this->CheckedCarefully[i][j] = 0;
      this->PointMapper[i][j] = -1;
    }
    for (int j = 0; j < numLinePts; j++)
    {
      this->ReversePointMapper[i][j] = -1;
    }
  }
  this->NewCellIds[0]->DeepCopy(this->IntersectionLines->GetCellData()->GetArray("NewCell0ID"));
  this->NewCellIds[1]->DeepCopy(this->IntersectionLines->GetCellData()->GetArray("NewCell1ID"));

  this->BooleanArray[0]->SetName("BooleanRegion");
  this->BooleanArray[1]->SetName("BooleanRegion");
  this->Mesh[0]->GetCellData()->AddArray(this->BooleanArray[0]);
  this->Mesh[0]->GetCellData()->SetActiveScalars("BooleanRegion");
  this->Mesh[1]->GetCellData()->AddArray(this->BooleanArray[1]);
  this->Mesh[1]->GetCellData()->SetActiveScalars("BooleanRegion");

  this->BoundaryCellArray[0]->SetName("BoundaryCells");
  this->BoundaryCellArray[1]->SetName("BoundaryCells");
  this->Mesh[0]->GetCellData()->AddArray(this->BoundaryCellArray[0]);
  this->Mesh[0]->GetCellData()->SetActiveScalars("BoundaryCells");
  this->Mesh[1]->GetCellData()->AddArray(this->BoundaryCellArray[1]);
  this->Mesh[1]->GetCellData()->SetActiveScalars("BoundaryCells");

  this->BoundaryPointArray[0]->SetName("BoundaryPoints");
  this->BoundaryPointArray[1]->SetName("BoundaryPoints");
  this->Mesh[0]->GetPointData()->AddArray(this->BoundaryPointArray[0]);
  this->Mesh[0]->GetPointData()->SetActiveScalars("BoundaryPoints");
  this->Mesh[1]->GetPointData()->AddArray(this->BoundaryPointArray[1]);
  this->Mesh[1]->GetPointData()->SetActiveScalars("BoundaryPoints");
}

// Function to find the regions on each input separated by the intersection
// lines
void vtkLoopBooleanPolyDataFilter::Impl::GetBooleanRegions(
  int inputIndex, std::vector<simLoop>* loops)
{
  vtkSmartPointer<vtkPolyData> tmpPolyData = vtkSmartPointer<vtkPolyData>::New();
  tmpPolyData->DeepCopy(this->Mesh[inputIndex]);
  tmpPolyData->BuildLinks();

  std::vector<simLoop>::iterator loopit;
  std::list<simLine>::iterator cellit;

  // For each intersection loop
  for (loopit = loops->begin(); loopit != loops->end(); ++loopit)
  {
    std::list<simLine> loopcells = (loopit)->cells;
    // Go through each cell in the loop
    for (cellit = loopcells.begin(); cellit != loopcells.end(); ++cellit)
    {
      simLine nextLine;
      nextLine = *cellit;
      vtkIdType nextCell = nextLine.id;
      vtkIdType p1 = nextLine.pt1;
      vtkIdType p2 = nextLine.pt2;
      vtkIdType outputCellId0 = this->NewCellIds[inputIndex]->GetComponent(nextCell, 0);
      vtkIdType outputCellId1 = this->NewCellIds[inputIndex]->GetComponent(nextCell, 1);
      // If the cell has not been given an orientation from the flood fill
      // algorithm and it has an id from vtkIntersectionPolyDataFilter
      if (outputCellId0 != -1)
      {
        // If the cell hasn't been touched
        if (this->CheckedCarefully[inputIndex][outputCellId0] == 0)
        {
          int sign1 = this->GetCellOrientation(tmpPolyData, outputCellId0, p1, p2, inputIndex);
          // If cell orientation is found
          if (sign1 != 0)
          {
            this->CheckCells->InsertNextId(outputCellId0);
            this->FindRegion(inputIndex, sign1, 1, 1);
            this->CheckCells->Reset();
            this->CheckCells2->Reset();
            this->CheckCellsCareful->Reset();
            this->CheckCellsCareful2->Reset();
          }
        }
      }
      // Check cell on other side of intersection line
      if (outputCellId1 != -1)
      {
        // If the cell hasn't been touched
        if (this->CheckedCarefully[inputIndex][outputCellId1] == 0)
        {
          int sign2 = this->GetCellOrientation(tmpPolyData, outputCellId1, p1, p2, inputIndex);
          // If cell orientation is found
          if (sign2 != 0)
          {
            this->CheckCells->InsertNextId(outputCellId1);
            this->FindRegion(inputIndex, sign2, 1, 1);
            this->CheckCells->Reset();
            this->CheckCells2->Reset();
            this->CheckCellsCareful->Reset();
            this->CheckCellsCareful2->Reset();
          }
        }
      }
    }
  }
}

// Get Cell orientation so we know which value to flood fill a region with
int vtkLoopBooleanPolyDataFilter::Impl::GetCellOrientation(
  vtkPolyData* pd, vtkIdType cellId, vtkIdType p0, vtkIdType p1, int index)
{
  vtkDebugWithObjectMacro(this->ParentFilter, << "CellId: " << cellId);
  vtkIdType npts;
  const vtkIdType* pts;
  pd->BuildLinks();
  pd->GetCellPoints(cellId, npts, pts);
  // pt0Id and pt1Id are from intersectionLines PolyData and I am trying
  // to compare these to the point ids in pd.
  vtkIdType cellPtId0 = this->ReversePointMapper[index][p0];
  vtkIdType cellPtId1 = this->ReversePointMapper[index][p1];
  double points[3][3];
  vtkIdType cellPtId2 = 0;
  for (int j = 0; j < npts; j++)
  {
    pd->GetPoint(pts[j], points[j]);
    if (cellPtId0 != pts[j] && cellPtId1 != pts[j])
    {
      cellPtId2 = pts[j];
    }
  }
  vtkSmartPointer<vtkPoints> cellPts = vtkSmartPointer<vtkPoints>::New();
  cellPts->InsertNextPoint(pd->GetPoint(cellPtId0));
  cellPts->InsertNextPoint(pd->GetPoint(cellPtId1));
  cellPts->InsertNextPoint(pd->GetPoint(cellPtId2));

  vtkSmartPointer<vtkPolyData> cellPD = vtkSmartPointer<vtkPolyData>::New();
  cellPD->SetPoints(cellPts);

  vtkSmartPointer<vtkCellArray> cellLines = vtkSmartPointer<vtkCellArray>::New();
  for (int j = 0; j < npts; j++)
  {
    int spot1 = j;
    int spot2 = (j + 1) % 3;
    cellLines->InsertNextCell(2);
    cellLines->InsertCellPoint(spot1);
    cellLines->InsertCellPoint(spot2);
  }
  cellPD->SetLines(cellLines);

  // Set up a transform that will rotate the points to the
  // XY-plane (normal aligned with z-axis).
  vtkSmartPointer<vtkTransform> transform = vtkSmartPointer<vtkTransform>::New();
  double zaxis[3] = { 0.0, 0.0, 1.0 };
  double rotationAxis[3], normal[3], center[3], rotationAngle;

  vtkTriangle::ComputeNormal(points[0], points[1], points[2], normal);

  double dotZAxis = vtkMath::Dot(normal, zaxis);
  if (fabs(1.0 - dotZAxis) < 1e-6)
  {
    // Aligned with z-axis
    rotationAxis[0] = 1.0;
    rotationAxis[1] = 0.0;
    rotationAxis[2] = 0.0;
    rotationAngle = 0.0;
  }
  else if (fabs(1.0 + dotZAxis) < 1e-6)
  {
    // Co-linear with z-axis, but reversed sense.
    // Aligned with z-axis
    rotationAxis[0] = 1.0;
    rotationAxis[1] = 0.0;
    rotationAxis[2] = 0.0;
    rotationAngle = 180.0;
  }
  else
  {
    // The general case
    vtkMath::Cross(normal, zaxis, rotationAxis);
    vtkMath::Normalize(rotationAxis);
    rotationAngle = vtkMath::DegreesFromRadians(acos(vtkMath::Dot(zaxis, normal)));
  }

  transform->PreMultiply();
  transform->Identity();

  vtkDebugWithObjectMacro(this->ParentFilter, << "ROTATION ANGLE " << rotationAngle);
  transform->RotateWXYZ(rotationAngle, rotationAxis[0], rotationAxis[1], rotationAxis[2]);

  vtkTriangle::TriangleCenter(points[0], points[1], points[2], center);
  transform->Translate(-center[0], -center[1], -center[2]);

  vtkSmartPointer<vtkTransformPolyDataFilter> transformer =
    vtkSmartPointer<vtkTransformPolyDataFilter>::New();
  transformer->SetInputData(cellPD);
  transformer->SetTransform(transform);
  transformer->Update();

  vtkSmartPointer<vtkPolyData> transPD = vtkSmartPointer<vtkPolyData>::New();
  transPD = transformer->GetOutput();
  transPD->BuildLinks();

  double area = 0;
  double tedgept1[3];
  double tedgept2[3];
  vtkIdType newpt;
  for (newpt = 0; newpt < transPD->GetNumberOfPoints() - 1; newpt++)
  {
    transPD->GetPoint(newpt, tedgept1);
    transPD->GetPoint(newpt + 1, tedgept2);
    area = area + (tedgept1[0] * tedgept2[1]) - (tedgept2[0] * tedgept1[1]);
  }
  transPD->GetPoint(newpt, tedgept1);
  transPD->GetPoint(0, tedgept2);
  area = area + (tedgept1[0] * tedgept2[1]) - (tedgept2[0] * tedgept1[1]);

  int value = 0;
  double tolerance = 1e-6;
  if (area < 0 && fabs(area) > tolerance)
  {
    value = -1;
  }
  else if (area > 0 && fabs(area) > tolerance)
  {
    value = 1;
  }
  else
  {
    vtkDebugWithObjectMacro(this->ParentFilter, << "Line pts are " << p0 << " and " << p1);
    vtkDebugWithObjectMacro(
      this->ParentFilter, << "PD pts are " << cellPtId0 << " and " << cellPtId1);
    value = 0;
  }

  return value;
}

// Reset the find region arrays to test another region
void vtkLoopBooleanPolyDataFilter::Impl::ResetCheckArrays()
{
  for (int i = 0; i < 2; i++)
  {
    int numPolys = this->Mesh[i]->GetNumberOfCells();
    for (vtkIdType cellId = 0; cellId < numPolys; cellId++)
    {
      if (this->BoundaryCellArray[i]->GetValue(cellId) == 1)
      {
        this->Checked[i][cellId] = 1;
        this->CheckedCarefully[i][cellId] = 0;
      }
      else
      {
        this->Checked[i][cellId] = 0;
        this->CheckedCarefully[i][cellId] = 1;
      }
    }
  }
}

// Set the boundary arrays on the mesh
void vtkLoopBooleanPolyDataFilter::Impl::SetBoundaryArrays()
{
  // Variables used in the function
  // Point locator to find points on mesh that are the points on the boundary
  // lines
  vtkSmartPointer<vtkPointLocator> pointLocator1 = vtkSmartPointer<vtkPointLocator>::New();
  vtkSmartPointer<vtkPointLocator> pointLocator2 = vtkSmartPointer<vtkPointLocator>::New();
  pointLocator1->SetDataSet(this->Mesh[0]);
  pointLocator1->BuildLocator();
  pointLocator2->SetDataSet(this->Mesh[1]);
  pointLocator2->BuildLocator();

  int numPoints = this->IntersectionLines->GetNumberOfPoints();

  for (vtkIdType pointId = 0; pointId < numPoints; pointId++)
  {
    double pt[3];
    this->IntersectionLines->GetPoint(pointId, pt);
    // Find point on mesh
    vtkIdType bp1 = pointLocator1->FindClosestPoint(pt);
    this->PointMapper[0][bp1] = pointId;
    this->ReversePointMapper[0][pointId] = bp1;
    this->BoundaryPointArray[0]->InsertValue(bp1, 1);
    vtkSmartPointer<vtkIdList> bpCellIds1 = vtkSmartPointer<vtkIdList>::New();
    this->Mesh[0]->GetPointCells(bp1, bpCellIds1);
    // Set the point mapping array
    // Assign each cell attached to this point as a boundary cell
    for (int i = 0; i < bpCellIds1->GetNumberOfIds(); i++)
    {
      this->BoundaryCellArray[0]->InsertValue(bpCellIds1->GetId(i), 1);
      this->Checked[0][bpCellIds1->GetId(i)] = 1;
    }

    vtkIdType bp2 = pointLocator2->FindClosestPoint(pt);
    this->PointMapper[1][bp2] = pointId;
    this->ReversePointMapper[1][pointId] = bp2;
    this->BoundaryPointArray[1]->InsertValue(bp2, 1);
    vtkSmartPointer<vtkIdList> bpCellIds2 = vtkSmartPointer<vtkIdList>::New();
    this->Mesh[1]->GetPointCells(bp2, bpCellIds2);
    // Set the point mapping array
    // Assign each cell attached to this point as a boundary cell
    for (int i = 0; i < bpCellIds2->GetNumberOfIds(); i++)
    {
      this->BoundaryCellArray[1]->InsertValue(bpCellIds2->GetId(i), 1);
      this->Checked[1][bpCellIds2->GetId(i)] = 1;
    }
  }
}

// Set the original finding region check arrays
void vtkLoopBooleanPolyDataFilter::Impl::SetCheckArrays()
{
  for (int i = 0; i < 2; i++)
  {
    // Get the number of Polys for scalar allocation
    int numPolys = this->Mesh[i]->GetNumberOfPolys();

    for (int j = 0; j < numPolys; j++)
    {
      if (this->Checked[i][j] == 0)
      {
        this->CheckedCarefully[i][j] = 1;
      }
      else
      {
        this->CheckedCarefully[i][j] = 0;
      }
    }
  }
}
//------------------------------------------------------------------------------

vtkStandardNewMacro(vtkLoopBooleanPolyDataFilter);

//------------------------------------------------------------------------------
vtkLoopBooleanPolyDataFilter::vtkLoopBooleanPolyDataFilter()
  : vtkPolyDataAlgorithm()
{
  this->Operation = VTK_UNION;

  this->SetNumberOfInputPorts(2);
  this->SetNumberOfOutputPorts(2);
  this->NoIntersectionOutput = 1;

  this->NumberOfIntersectionPoints = 0;
  this->NumberOfIntersectionLines = 0;

  this->Status = 1;
  this->Tolerance = 1e-6;
}

//------------------------------------------------------------------------------
vtkLoopBooleanPolyDataFilter::~vtkLoopBooleanPolyDataFilter() = default;

//------------------------------------------------------------------------------
int vtkLoopBooleanPolyDataFilter::RequestData(vtkInformation* vtkNotUsed(request),
  vtkInformationVector** inputVector, vtkInformationVector* outputVector)
{
  vtkInformation* inInfo0 = inputVector[0]->GetInformationObject(0);
  vtkInformation* inInfo1 = inputVector[1]->GetInformationObject(0);
  vtkInformation* outInfo0 = outputVector->GetInformationObject(0);
  vtkInformation* outInfo1 = outputVector->GetInformationObject(1);

  if (!inInfo0 || !inInfo1 || !outInfo0 || !outInfo1)
  {
    this->Status = 0;
    return 0;
  }

  vtkPolyData* input0 = vtkPolyData::SafeDownCast(inInfo0->Get(vtkDataObject::DATA_OBJECT()));
  vtkPolyData* input1 = vtkPolyData::SafeDownCast(inInfo1->Get(vtkDataObject::DATA_OBJECT()));

  vtkPolyData* outputSurface =
    vtkPolyData::SafeDownCast(outInfo0->Get(vtkDataObject::DATA_OBJECT()));
  vtkPolyData* outputIntersection =
    vtkPolyData::SafeDownCast(outInfo1->Get(vtkDataObject::DATA_OBJECT()));

  if (!input0 || !input1 || !outputSurface || !outputIntersection)
  {
    this->Status = 0;
    return 0;
  }

  // Get intersected versions
  vtkSmartPointer<vtkIntersectionPolyDataFilter> polydataIntersection =
    vtkSmartPointer<vtkIntersectionPolyDataFilter>::New();
  polydataIntersection->SetInputConnection(0, this->GetInputConnection(0, 0));
  polydataIntersection->SetInputConnection(1, this->GetInputConnection(1, 0));
  polydataIntersection->SplitFirstOutputOn();
  polydataIntersection->SplitSecondOutputOn();
  polydataIntersection->SetTolerance(this->Tolerance);
  polydataIntersection->Update();
  if (polydataIntersection->GetStatus() != 1)
  {
    this->Status = 0;
    return 0;
  }

  this->NumberOfIntersectionPoints = polydataIntersection->GetNumberOfIntersectionPoints();
  this->NumberOfIntersectionLines = polydataIntersection->GetNumberOfIntersectionLines();

  vtkDebugMacro(<< "Intersection is Done!!!");

  vtkLoopBooleanPolyDataFilter::Impl* impl = new vtkLoopBooleanPolyDataFilter::Impl();
  impl->ParentFilter = this;
  impl->Mesh[0]->DeepCopy(polydataIntersection->GetOutput(1));
  impl->Mesh[0]->BuildLinks();
  impl->Mesh[1]->DeepCopy(polydataIntersection->GetOutput(2));
  impl->Mesh[1]->BuildLinks();
  impl->IntersectionLines->ShallowCopy(polydataIntersection->GetOutput(0));

  if (this->NumberOfIntersectionPoints == 0 || this->NumberOfIntersectionLines == 0)
  {
    vtkWarningMacro(<< "No intersections!");
    if (this->NoIntersectionOutput == 0)
    {
      delete impl;
      return 1;
    }
    else
    {
      for (int i = 0; i < 2; i++)
      {
        // Get the number of Polys for scalar allocation
        int numPolys = impl->Mesh[i]->GetNumberOfPolys();
        int numPts = impl->Mesh[i]->GetNumberOfPoints();
        for (int j = 0; j < numPts; j++)
        {
          impl->BoundaryPointArray[i]->InsertValue(j, 0);
        }

        for (int j = 0; j < numPolys; j++)
        {
          impl->BoundaryCellArray[i]->InsertValue(j, 0);
        }

        impl->BoundaryCellArray[i]->SetName("BoundaryCells");
        impl->Mesh[i]->GetCellData()->AddArray(impl->BoundaryCellArray[i]);
        impl->Mesh[i]->GetCellData()->SetActiveScalars("BoundaryCells");

        impl->BoundaryPointArray[i]->SetName("BoundaryPoints");
        impl->Mesh[i]->GetPointData()->AddArray(impl->BoundaryPointArray[i]);
        impl->Mesh[i]->GetPointData()->SetActiveScalars("BoundaryPoints");
      }
      if (this->NoIntersectionOutput == 1)
      {
        vtkDebugMacro(<< "Only returning first surface");
        outputSurface->DeepCopy(impl->Mesh[0]);
      }
      else if (this->NoIntersectionOutput == 2)
      {
        vtkDebugMacro(<< "Only returning second surface");
        outputSurface->DeepCopy(impl->Mesh[1]);
      }
      else
      {
        vtkDebugMacro(<< "Keeping both");

        vtkSmartPointer<vtkAppendPolyData> appender = vtkSmartPointer<vtkAppendPolyData>::New();
        appender->AddInputData(impl->Mesh[0]);
        appender->AddInputData(impl->Mesh[1]);
        appender->Update();
        outputSurface->DeepCopy(appender->GetOutput());
      }
      delete impl;
      return 1;
    }
  }

  double badtri1[2], badtri2[2];
  double freeedge1[2], freeedge2[2];
  impl->Mesh[0]->GetCellData()->GetArray("BadTriangle")->GetRange(badtri1, 0);
  impl->Mesh[0]->GetCellData()->GetArray("FreeEdge")->GetRange(freeedge1, 0);

  impl->Mesh[1]->GetCellData()->GetArray("BadTriangle")->GetRange(badtri2, 0);
  impl->Mesh[1]->GetCellData()->GetArray("FreeEdge")->GetRange(freeedge2, 0);

  // Set the check and boundary arrays for region finding
  vtkDebugMacro(<< "Initializing");
  impl->Initialize();
  vtkDebugMacro(<< "Setting Bound Arrays");
  impl->SetBoundaryArrays();
  vtkDebugMacro(<< "Setting Check Arrays");
  impl->SetCheckArrays();

  // Determine the intersection type and obtain the intersection loops
  // to give to Boolean Region finding
  vtkDebugMacro(<< "Determining Intersection Type");
  std::vector<simLoop> loops;
  impl->DetermineIntersection(&loops);

  // Get the regions bounded by the intersection lines and give correct
  // orientation
  impl->GetBooleanRegions(0, &loops);
  vtkDebugMacro(<< "DONE WITH 1");
  impl->GetBooleanRegions(1, &loops);
  vtkDebugMacro(<< "DONE WITH 2");

  // Combine certain orientations based on the operation desired
  impl->PerformBoolean(outputSurface, this->Operation);

  // Number of bad triangles and free edges (Should be zero for watertight,
  // manifold surfaces!
  vtkDebugMacro(<< "SURFACE 1 BAD TRI MIN: " << badtri1[0] << " MAX: " << badtri1[1]);
  vtkDebugMacro(<< "SURFACE 1 FREE EDGE MIN: " << freeedge1[0] << " MAX: " << freeedge1[1]);
  vtkDebugMacro(<< "SURFACE 2 BAD TRI MIN: " << badtri2[0] << " MAX: " << badtri2[1]);
  vtkDebugMacro(<< "SURFACE 2 FREE EDGE MIN: " << freeedge2[0] << " MAX: " << freeedge2[1]);

  double fullbadtri[2], fullfreeedge[2], dummy[2];
  vtkIntersectionPolyDataFilter::CleanAndCheckSurface(outputSurface, dummy, this->Tolerance);
  outputSurface->GetCellData()->GetArray("BadTriangle")->GetRange(fullbadtri, 0);
  outputSurface->GetCellData()->GetArray("FreeEdge")->GetRange(fullfreeedge, 0);

  // Add Normals
  vtkSmartPointer<vtkPolyDataNormals> normaler = vtkSmartPointer<vtkPolyDataNormals>::New();
  normaler->SetInputData(outputSurface);
  normaler->AutoOrientNormalsOn();
  normaler->Update();
  outputSurface->DeepCopy(normaler->GetOutput());

  vtkDebugMacro(<< "FULL SURFACE BAD TRI MIN: " << fullbadtri[0]);
  vtkDebugMacro(<< " MAX: " << fullbadtri[1]);
  vtkDebugMacro(<< "FULL SURFACE FREE EDGE MIN: " << fullfreeedge[0]);
  vtkDebugMacro(<< " MAX: " << fullfreeedge[1]);

  delete impl;
  return 1;
}

//------------------------------------------------------------------------------
void vtkLoopBooleanPolyDataFilter::PrintSelf(ostream& os, vtkIndent indent)
{
  this->Superclass::PrintSelf(os, indent);

  os << indent << "Operation: ";
  switch (this->Operation)
  {
    case VTK_UNION:
      os << "UNION";
      break;

    case VTK_INTERSECTION:
      os << "INTERSECTION";
      break;

    case VTK_DIFFERENCE:
      os << "DIFFERENCE";
      break;
  }
  os << "\n";
  os << indent << "No Intersection Output: " << this->NoIntersectionOutput << "\n";
  os << indent << "Tolerance: " << this->Tolerance << "\n";
  os << indent << "NumberOfIntersectionPoints: " << this->NumberOfIntersectionPoints << "\n";
  os << indent << "NumberOfIntersectionLines: " << this->NumberOfIntersectionLines << "\n";
}

//------------------------------------------------------------------------------
int vtkLoopBooleanPolyDataFilter::FillInputPortInformation(int port, vtkInformation* info)
{
  if (!this->Superclass::FillInputPortInformation(port, info))
  {
    return 0;
  }
  if (port == 0)
  {
    info->Set(vtkAlgorithm::INPUT_REQUIRED_DATA_TYPE(), "vtkPolyData");
  }
  else if (port == 1)
  {
    info->Set(vtkAlgorithm::INPUT_REQUIRED_DATA_TYPE(), "vtkPolyData");
    info->Set(vtkAlgorithm::INPUT_IS_OPTIONAL(), 0);
  }
  return 1;
}

//------------------------------------------------------------------------------

// Determine type of intersection
void vtkLoopBooleanPolyDataFilter::Impl::DetermineIntersection(std::vector<simLoop>* loops)
{
  int numInterPts = this->IntersectionLines->GetNumberOfPoints();
  bool* usedPt;
  usedPt = new bool[numInterPts];
  for (vtkIdType interPt = 0; interPt < numInterPts; interPt++)
  {
    usedPt[interPt] = false;
  }

  for (vtkIdType interPt = 0; interPt < numInterPts; interPt++)
  {
    if (usedPt[interPt] == false)
    {
      simLoop newloop;
      vtkSmartPointer<vtkIdList> cellIds = vtkSmartPointer<vtkIdList>::New();
      this->IntersectionLines->GetPointCells(interPt, cellIds);
      if (cellIds->GetNumberOfIds() > 2)
      {
        vtkDebugWithObjectMacro(
          this->ParentFilter, << "Number Of Cells is greater than 2 for first point " << interPt);
      }
      else if (cellIds->GetNumberOfIds() < 2)
      {
        vtkDebugWithObjectMacro(
          this->ParentFilter, << "Number Of Cells is less than 2 for point " << interPt);
      }

      vtkIdType nextCell = cellIds->GetId(0);

      // Run through intersection lines to get loops!
      newloop.startPt = interPt;
      int caseId = 0;
      caseId = this->RunLoopFind(interPt, nextCell, usedPt, &newloop);
      if (caseId != -1)
      {
        // If the intersection loop is open
        if (this->IntersectionCase == 2)
        {
          vtkIdType nextPt = caseId;
          vtkDebugWithObjectMacro(this->ParentFilter, << "End point of open loop is " << nextPt);
          newloop.endPt = nextPt;
          newloop.loopType = 2;
          nextCell = cellIds->GetId(1);
          vtkIdType newId = this->RunLoopFind(interPt, nextCell, usedPt, &newloop);
          newloop.startPt = newId;
          // Save start and end point in custom data structure for loop
        }
        else
        {
          newloop.loopType = 1;
        }
      }
      usedPt[interPt] = true;
      loops->push_back(newloop);
    }
  }
  vtkDebugWithObjectMacro(this->ParentFilter, << "Number Of Loops: " << loops->size());

  delete[] usedPt;
}

// Function for if the intersection is soft closed or open
int vtkLoopBooleanPolyDataFilter::Impl::RunLoopFind(
  vtkIdType interPt, vtkIdType nextCell, bool* usedPt, simLoop* loop)
{
  vtkIdType prevPt = interPt;
  vtkIdType nextPt = interPt;
  vtkSmartPointer<vtkIdList> pointIds = vtkSmartPointer<vtkIdList>::New();
  vtkSmartPointer<vtkIdList> cellIds = vtkSmartPointer<vtkIdList>::New();

  IntersectionLines->GetCellPoints(nextCell, pointIds);
  if (pointIds->GetNumberOfIds() > 2)
  {
    vtkDebugWithObjectMacro(
      this->ParentFilter, << "Number Of Points is greater than 2 for first cell " << nextCell);
  }
  else if (pointIds->GetNumberOfIds() < 2)
  {
    vtkDebugWithObjectMacro(
      this->ParentFilter, << "Number Of Points is less than 2 for first cell " << nextCell);
  }

  if (pointIds->GetId(0) == nextPt)
  {
    nextPt = pointIds->GetId(1);
  }
  else
  {
    nextPt = pointIds->GetId(0);
  }
  simLine newline;
  newline.pt1 = prevPt;
  newline.pt2 = nextPt;
  newline.id = nextCell;
  loop->cells.push_back(newline);

  usedPt[nextPt] = true;
  while (nextPt != loop->cells.front().pt1)
  {
    IntersectionLines->GetPointCells(nextPt, cellIds);
    if (cellIds->GetNumberOfIds() > 2)
    {
      IntersectionCase = 1;
      vtkDebugWithObjectMacro(
        this->ParentFilter, << "Number Of Cells is greater than 2 for point " << nextPt);
      usedPt[nextPt] = false;
      nextCell = this->RunLoopTest(nextPt, nextCell, loop, usedPt);
      if (nextCell == -1)
      {
        break;
      }
      vtkDebugWithObjectMacro(this->ParentFilter, << "Next cell is " << nextCell);
    }
    else if (cellIds->GetNumberOfIds() < 2)
    {
      vtkDebugWithObjectMacro(
        this->ParentFilter, << "Number Of Cells is less than 2 for point " << nextPt);
      IntersectionCase = 2;
      return nextPt;
    }
    else
    {
      if (cellIds->GetId(0) == nextCell)
      {
        nextCell = cellIds->GetId(1);
      }
      else
      {
        nextCell = cellIds->GetId(0);
      }
    }

    IntersectionLines->GetCellPoints(nextCell, pointIds);
    if (pointIds->GetNumberOfIds() > 2)
    {
      vtkDebugWithObjectMacro(
        this->ParentFilter, << "Number Of Points is greater than 2 for cell " << nextCell);
    }
    else if (pointIds->GetNumberOfIds() < 2)
    {
      vtkDebugWithObjectMacro(
        this->ParentFilter, << "Number Of Points is less than 2 for first cell " << nextCell);
    }
    prevPt = nextPt;
    if (pointIds->GetId(0) == nextPt)
    {
      nextPt = pointIds->GetId(1);
    }
    else
    {
      nextPt = pointIds->GetId(0);
    }
    usedPt[nextPt] = true;

    simLine newestline;
    newestline.pt1 = prevPt;
    newestline.pt2 = nextPt;
    newestline.id = nextCell;
    loop->cells.push_back(newestline);
  }
  loop->endPt = nextPt;
  loop->loopType = 0;
  vtkDebugWithObjectMacro(this->ParentFilter, << "Start and End Point are " << nextPt);

  return -1;
}

// Tests an orientation in a specified region
int vtkLoopBooleanPolyDataFilter::Impl::RunLoopTest(
  vtkIdType interPt, vtkIdType nextCell, simLoop* loop, bool* usedPt)
{
  // This test is only if the intersection has soft closed loops
  vtkDebugWithObjectMacro(this->ParentFilter, << "Running Loop Test to find right loop");
  vtkIdType stopCell = nextCell;
  vtkIdType prevPt = interPt;
  vtkIdType nextPt = interPt;
  vtkSmartPointer<vtkIdList> pointIds = vtkSmartPointer<vtkIdList>::New();
  vtkSmartPointer<vtkPolyData> tmpPolyData = vtkSmartPointer<vtkPolyData>::New();
  int input = 0;
  tmpPolyData->DeepCopy(this->Mesh[input]);
  tmpPolyData->BuildLinks();
  std::list<simLine>::iterator cellit;

  vtkSmartPointer<vtkIdList> cellIds = vtkSmartPointer<vtkIdList>::New();
  IntersectionLines->GetPointCells(nextPt, cellIds);
  vtkDebugWithObjectMacro(this->ParentFilter,
    << "Number of cells should be more than two!! " << cellIds->GetNumberOfIds());
  for (vtkIdType i = 0; i < cellIds->GetNumberOfIds(); i++)
  {
    int numRegionsFound = 0;
    vtkIdType cellId = cellIds->GetId(i);
    vtkDebugWithObjectMacro(this->ParentFilter, << "Testing cell " << cellId);
    IntersectionLines->GetCellPoints(cellId, pointIds);
    if (pointIds->GetNumberOfIds() > 2)
    {
      vtkDebugWithObjectMacro(
        this->ParentFilter, << "Number Of Points is greater than 2 for first cell " << nextCell);
    }
    else if (pointIds->GetNumberOfIds() < 2)
    {
      vtkDebugWithObjectMacro(
        this->ParentFilter, << "Number Of Points is less than 2 for first cell " << nextCell);
    }

    if (pointIds->GetId(0) == interPt)
    {
      nextPt = pointIds->GetId(1);
    }
    else
    {
      nextPt = pointIds->GetId(0);
    }

    if (usedPt[nextPt] == true)
    {
      vtkDebugWithObjectMacro(this->ParentFilter, << "Bad One");
    }
    if (cellId != stopCell && usedPt[nextPt] != true)
    {
      simLine newline;
      newline.id = cellId;
      newline.pt1 = prevPt;
      newline.pt2 = nextPt;
      loop->cells.push_back(newline);
      vtkDebugWithObjectMacro(this->ParentFilter, << "Cell id is: " << cellId);
      for (cellit = loop->cells.begin(); cellit != loop->cells.end(); ++cellit)
      {
        simLine nextLine;
        nextLine = *cellit;
        nextCell = nextLine.id;
        vtkIdType p1 = nextLine.pt1;
        vtkIdType p2 = nextLine.pt2;
        vtkDebugWithObjectMacro(this->ParentFilter, << "Line cell is " << nextCell);
        vtkIdType outputCellId0 = this->NewCellIds[input]->GetComponent(nextCell, 0);
        vtkIdType outputCellId1 = this->NewCellIds[input]->GetComponent(nextCell, 1);
        if (outputCellId0 != -1)
        {
          if (this->CheckedCarefully[input][outputCellId0] == 0)
          {
            int sign1 = this->GetCellOrientation(tmpPolyData, outputCellId0, p1, p2, input);
            if (sign1 == -1)
            {
              numRegionsFound++;
              this->CheckCells->InsertNextId(outputCellId0);
              this->FindRegion(input, sign1, 1, 0);
              this->CheckCells->Reset();
              this->CheckCells2->Reset();
              this->CheckCellsCareful->Reset();
              this->CheckCellsCareful2->Reset();
            }
          }
        }
        if (outputCellId1 != -1)
        {
          if (this->CheckedCarefully[input][outputCellId1] == 0)
          {
            int sign2 = this->GetCellOrientation(tmpPolyData, outputCellId1, p1, p2, input);
            if (sign2 == -1)
            {
              numRegionsFound++;
              this->CheckCells->InsertNextId(outputCellId1);
              this->FindRegion(input, sign2, 1, 0);
              this->CheckCells->Reset();
              this->CheckCells2->Reset();
              this->CheckCellsCareful->Reset();
              this->CheckCellsCareful2->Reset();
            }
          }
        }
      }
      loop->cells.pop_back();
      this->ResetCheckArrays();
      vtkDebugWithObjectMacro(
        this->ParentFilter, << "Number of Regions Found: " << numRegionsFound);
      if (numRegionsFound == 1)
      {
        vtkDebugWithObjectMacro(this->ParentFilter, << "Legitimate Loop found");
        return cellId;
      }
    }
  }
  vtkDebugWithObjectMacro(this->ParentFilter, << "Start and End Point are " << nextPt);

  return -1;
}

// Combine the correct regions for output boolean
void vtkLoopBooleanPolyDataFilter::Impl::PerformBoolean(vtkPolyData* output, int booleanOperation)
{
  // vtkSmartPointer<vtkThreshold> thresholder =
  //  vtkSmartPointer<vtkThreshold>::New();
  // vtkSmartPointer<vtkDataSetSurfaceFilter> surfacer =
  //  vtkSmartPointer<vtkDataSetSurfaceFilter>::New();

  vtkPolyData* surfaces[4];
  for (int i = 0; i < 4; i++)
  {
    surfaces[i] = vtkPolyData::New();
  }

  this->ThresholdRegions(surfaces);
  // thresholder->SetInputData(this->Mesh[0]);
  // thresholder->SetInputArrayToProcess(0, 0, 0, 1, "BooleanRegion");
  // thresholder->ThresholdBetween(-1, -1);
  // thresholder->Update();
  // surfacer->SetInputData(thresholder->GetOutput());
  // surfacer->Update();
  // surfaces[0]->DeepCopy(surfacer->GetOutput());

  // thresholder->SetInputData(this->Mesh[0]);
  // thresholder->SetInputArrayToProcess(0, 0, 0, 1, "BooleanRegion");
  // thresholder->ThresholdBetween(1, 1);
  // thresholder->Update();
  // surfacer->SetInputData(thresholder->GetOutput());
  // surfacer->Update();
  // surfaces[1]->DeepCopy(surfacer->GetOutput());

  // thresholder->SetInputData(this->Mesh[1]);
  // thresholder->SetInputArrayToProcess(0, 0, 0, 1, "BooleanRegion");
  // thresholder->ThresholdBetween(1, 1);
  // thresholder->Update();
  // surfacer->SetInputData(thresholder->GetOutput());
  // surfacer->Update();
  // surfaces[2]->DeepCopy(surfacer->GetOutput());

  // thresholder->SetInputData(this->Mesh[1]);
  // thresholder->SetInputArrayToProcess(0, 0, 0, 1, "BooleanRegion");
  // thresholder->ThresholdBetween(-1, -1);
  // thresholder->Update();
  // surfacer->SetInputData(thresholder->GetOutput());
  // surfacer->Update();
  // surfaces[3]->DeepCopy(surfacer->GetOutput());

  vtkSmartPointer<vtkAppendPolyData> appender = vtkSmartPointer<vtkAppendPolyData>::New();

  // If open intersection case, make sure correct region is taken
  if (this->IntersectionCase == 2)
  {
    vtkSmartPointer<vtkPolyData> tmp = vtkSmartPointer<vtkPolyData>::New();
    int numCells[4];
    std::list<vtkIdType> nocellregion;
    for (int i = 0; i < 4; i++)
    {
      numCells[i] = surfaces[i]->GetNumberOfCells();
      if (numCells[i] == 0)
      {
        nocellregion.push_back(i);
      }
    }
    if (!nocellregion.empty())
    {
      if (nocellregion.front() == 0)
      {
        tmp->DeepCopy(surfaces[1]);
        surfaces[1]->DeepCopy(surfaces[0]);
        surfaces[0]->DeepCopy(tmp);
      }
      if (nocellregion.back() == 2)
      {
        tmp->DeepCopy(surfaces[3]);
        surfaces[3]->DeepCopy(surfaces[2]);
        surfaces[2]->DeepCopy(tmp);
      }
    }
  }
  if (booleanOperation == 0)
  {
    appender->AddInputData(surfaces[0]);
    appender->AddInputData(surfaces[2]);
  }
  if (booleanOperation == 1)
  {
    appender->AddInputData(surfaces[1]);
    appender->AddInputData(surfaces[3]);
  }
  if (booleanOperation == 2)
  {
    appender->AddInputData(surfaces[0]);
    appender->AddInputData(surfaces[3]);
  }
  appender->Update();

  output->DeepCopy(appender->GetOutput());

  for (int i = 0; i < 4; i++)
  {
    surfaces[i]->Delete();
  }
}

void vtkLoopBooleanPolyDataFilter::Impl::ThresholdRegions(vtkPolyData** surfaces)
{
  vtkPoints* points[4];
  vtkCellArray* cells[4];
  vtkIntArray* boundaryPoints[4];
  vtkIntArray* boundaryCells[4];
  vtkIntArray* booleanCells[4];

  for (int i = 0; i < 4; i++)
  {
    points[i] = vtkPoints::New();
    cells[i] = vtkCellArray::New();
    boundaryPoints[i] = vtkIntArray::New();
    boundaryCells[i] = vtkIntArray::New();
    booleanCells[i] = vtkIntArray::New();
  }

  for (int i = 0; i < 2; i++)
  {
    int numCells = this->Mesh[i]->GetNumberOfCells();
    for (int j = 0; j < numCells; j++)
    {
      int value = this->BooleanArray[i]->GetValue(j);
      vtkIdType npts;
      const vtkIdType* pts;
      this->Mesh[i]->GetCellPoints(j, npts, pts);
      if (value < 0)
      {
        vtkSmartPointer<vtkIdList> newPointIds = vtkSmartPointer<vtkIdList>::New();
        newPointIds->SetNumberOfIds(3);
        for (int k = 0; k < npts; k++)
        {
          double pt[3];
          this->Mesh[i]->GetPoint(pts[k], pt);
          vtkIdType newId = points[3 * i]->InsertNextPoint(pt);
          newPointIds->SetId(k, newId);
          boundaryPoints[3 * i]->InsertValue(newId, this->BoundaryPointArray[i]->GetValue(pts[k]));
        }
        vtkIdType cellId = cells[3 * i]->InsertNextCell(newPointIds);
        boundaryCells[3 * i]->InsertValue(cellId, this->BoundaryCellArray[i]->GetValue(j));
        booleanCells[3 * i]->InsertValue(cellId, this->BooleanArray[i]->GetValue(j));
      }
      if (value > 0)
      {
        vtkSmartPointer<vtkIdList> newPointIds = vtkSmartPointer<vtkIdList>::New();
        newPointIds->SetNumberOfIds(3);
        for (int k = 0; k < npts; k++)
        {
          double pt[3];
          this->Mesh[i]->GetPoint(pts[k], pt);
          vtkIdType newId = points[i + 1]->InsertNextPoint(pt);
          newPointIds->SetId(k, newId);
          boundaryPoints[i + 1]->InsertValue(newId, this->BoundaryPointArray[i]->GetValue(pts[k]));
        }
        vtkIdType cellId = cells[i + 1]->InsertNextCell(newPointIds);
        boundaryCells[i + 1]->InsertValue(cellId, this->BoundaryCellArray[i]->GetValue(j));
        booleanCells[i + 1]->InsertValue(cellId, this->BooleanArray[i]->GetValue(j));
      }
    }
  }
  for (int i = 0; i < 4; i++)
  {
    surfaces[i]->SetPoints(points[i]);
    surfaces[i]->SetPolys(cells[i]);
    surfaces[i]->BuildLinks();
    boundaryPoints[i]->SetName("BoundaryPoints");
    surfaces[i]->GetPointData()->AddArray(boundaryPoints[i]);
    boundaryCells[i]->SetName("BoundaryCells");
    surfaces[i]->GetCellData()->AddArray(boundaryCells[i]);
    booleanCells[i]->SetName("BooleanRegion");
    surfaces[i]->GetCellData()->AddArray(booleanCells[i]);

    points[i]->Delete();
    cells[i]->Delete();
    boundaryPoints[i]->Delete();
    boundaryCells[i]->Delete();
    booleanCells[i]->Delete();
  }
}
